How tro automate a vintage Sawyer Rotodisc

[Thoughtsprocket]

Greetings Everyone. I'm a graduate student of interdisciplinary art who is fairly digital savvy, but not electrically savvy when it comes to hacking analogue devices. I need advice on how I can automate a vintage projector. The slides are advanced manually. I need them to advance automatically. Perhaps some of you might ask why even use a vintage slide projector at all with all of the new technology available to us today. Good question! Well, my graduate work is focused on memory, so the slide projectors are a way to consider the past as ever present. I want to create two banks of projectors. One bank of projectors will be Sawyer 2 x2 Rotodisc Projectors with rotodiscs filled with my own 35mm work. The other bank will be made up of Viewmaster Projectors hat will project images of my own contemporary work. I am curious to know how to automate these kinds of projectors, and how to "link" them together. Thus far all of my art installation projections are the usual large wall projections or projections onto objects using Epson projectors with Macbook Pro laptops. I have never used Arduino or Max. Is this the way I should go with these projects or is there some other more rudimentary electrical way to do this? Any answers are greatly appreciated. I'd be very happy at this point just to learn how to do the most basic automation.

 

[tronitech]

Solenoids may do it but you'd have to find ones with the required force and movement?

 

[Thoughtsprocket]

Thank you, Tronitech. Forgive my lack of knowledge. I certainly understand what a solenoid is, and how to figure out the movement. Please, can you tell me how to find out the required force? What's a good starting point? Many thanks!

 

[shortbus=]

You could use a 'fish scale'. Hook one side of the scale to the lever and pull to activate it, to see how much force is needed.
https://www.cabelas.com/product/Ber...t=fish+scale&WTz_l=Header;Search-All+Products

 

[JonSea]

Kodak Caroselle projectors have an electrically controlled advance mechanism built in, so they could remove the need for a mechanical interface. They can often be found at thrift stores these days.

 

[Thoughtsprocket]

Yes. Thank you, JonSea. Unfortunately they do not have the appearance I need for the installation. Shortbus=, hm, I would have never thought of that idea. Thank you!

 

[Mickster]

How about using the wiper motor from an automobile, along with the intermittent wipe relay?
Connect the short arm to the advance knob and modify the intermittent wipe circuit, to give the required interval.

 

[Thoughtsprocket]

Mickster, Best thing I've heard to date! I'm going to give it a try! Now the only thing is how do I modify the intermittent wipe circuit? Can you pint me to some directions on line?

 

[KeepItSimpleStupid]

Yea, you really need the:

Force required
The motion required: e.g. straight line
How much motion is required: e.g. length of travel
And what sort of motion is needed. e.g. push and release
How fast?

There is also the idea of just simple rotary motion and sensors.

You also need to look at the speed at which this is to happen.

The "fish scale" or "luggage scale" or "spring scale" is a way of measuring force. Another way to estimate is with weights. e.g. to measure the force required to pull a drapary closed, attach cans of various weights until it moves. So, you can get the force in lbs or ounces.

It you wanted a motor to move the cord, you would need torque and those units are in oz-in, for instance.

A "door lock actuator" https://auto.howstuffworks.com/power-door-lock3.htm might be a place to start. This https://www.amazon.com/High-Power-Door-Lock-Actuator/dp/B0002KR9PW has on 3/4" of travel.

An AC synchronous motor and a rack and pinion with limits might also work.

Adjustable clutches like these https://www.sdp-si.com/eStore/Catalog (S98CA6-MOC200424 ) protect what your driving

There are so many different ways.

Here **broken link removed** is a little gizmo. You mount the switches to limit the travel with the proper controller.

There were two systems I was involved in. One used a 24 position rotary solenoid, That was a strange beast.

In another case, I had to rotate four 2"x2" filters into an optical path. I placed a roller micro switch on the edge of the wheel and an indentation for each filter. I used 2 "hall effect" sensors to get the position "00" "01", "10" and "11". My controller knew when the motor was moving or stopped and I could tell the motor to ignore the switch.

Other systems were shutters.

Your motion could be press and release. much like the door lock.

Slide projector mechanisms were very slow and were prone to jamming. The one I had actually moved the slide and then put it back into the carousel,

Stepper motors are another option.

I'll throw air as an option too. e.g. a double acting air cylinder. Tricky to set up.

 

[shortbus=]

How about using the wiper motor from an automobile, along with the intermittent wipe relay?
Connect the short arm to the advance knob and modify the intermittent wipe circuit, to give the required interval.

Only trouble with that is a wiper motor itself is rotary motion. The linkage (belcranks, links and levers) change it to back and forth.

A RC servo might be used if the force needed is small enough.

 

[Thoughtsprocket]

Wow! KeepItSimpleStupid, I'm overwhelmed by your response. Thank you! I'm getting a bigger picture just by all that you wrote. You are awesome!

 

[Thoughtsprocket]

I see, Shortbus=. I'm going to try out a number of the suggestions here. They're things I had not thought of. I'll post the results in a few months time...after I pass my next board review. Wish me luck! I'm really glad I joined Electro-Tech. You are all super folks! Thank you. If anyone needs help with art, hit me up!

 

[KeepItSimpleStupid]

Shortbus= has a decent idea too. See here https://www.pololu.com/product/2147 This would be like putting an 18 lb weight on the lever at 1". the arm length reduces the effective force. So, if at 1", it's 280 oz and at 2" it would be half that. 140 oz. Pololu has some interesting controllers too.

If you need some sort of other controller, the Arduino and the PICAXE (www.picaxe.com) might work for you.

Ask at your school machine shop if you have one.